The present invention relates in general to cotton gins, and more particularly to saw type cotton gins having novel means for removing ginned cotton seed from the roll box in a manner to provide a significant increase in the capacity of cotton gins already having the most advanced known features for providing optimum ginning capacity.
During recent years, the ginning capacity of cotton gins of the saw type has been increased without changing the basic components or fundamental principle of operation of the gins, for example by providing so called larger diameter saw cylinders having saws of about 16-inch diameter driven at high speed, associated with ginning ribs and huller ribs of various designs, whereby greater capacity, for example in the range of 7 to 10 bales per hour, can be realized due to the greater peripheral speed of the saw teeth of such larger diameter saw cylinders and the improved design of the ginning ribs and huller ribs. However, the fundamental elements making up the gin stand were not significantly changed. The ginned seeds were still discharged out the bottom of the gin stand, through the spaces between the saws of the saw cylinder in the region between the ginning ribs and the huller ribs, and thence by gravity feed into the transverse trough in the working zone of the transverse seed conveyor at the bottom of the gin to be conveyed to the disposal location.
It is well recognized that the incoming seed cotton in the feed chute of a conventional saw type gin stand is carried by engagement of the saw teeth with the lint on the seeds into the seed roll in the roll box immediately above the zone between the ginning ribs and the huller ribs where the mix of ginned cotton seeds and unginned cotton is maintained in the form of a relatively compact roll with the perimeter of the seed roll being continuously worked by the saw teeth. The saw teeth engage and pull lint from the seeds in the perimeter of the seed roll through the narrow spaces at the ginning point between the ginning ribs while the seeds are retained in the roll box region by the ginning ribs. The ginned seeds in the seed roll are continuously trying to leave the seed roll and fall through the entrance to the roll box and the seed discharge spaces between the saws of the cylinder in the seed discharge passage zone between the ginning ribs and huller ribs while the saws are trying to bring additional unginned seeds from the feed chute through this same seed passage zone and roll box entrance into the seed roll in the roll box. Thus it has been recognized for many years that the capacity of a gin stand is limited by its inability to discharge the ginned seed with sufficient rapidity from the seed roll in a manner which will reduce seed roll density to desired levels and admit new unginned seed cotton at greater rate to the roll box. The ginned seeds restrained in the seed roll severely limit the ginning capacity because they increase the density of the roll making it difficult for the saw teeth to be fully loaded with lint and the ginned seed trying to get out of the roll box by falling through the roll box entrance where the incoming unginned seed is trying to enter exerts a feed counterforce by fighting the entrance of unginned seed into the roll box.
We have discovered that the capacity of high capacity gin stands of the most advanced design already on the market can be dramatically increased by continuously removing ginned seed from the general area of the midregion of the seed roll in the roll box during the operation of the gin, by providing a driven rotating perforated tube which transversely spans the box and having perforations sized to pass the ginned seeds into the tube for removal by suitable continuously operating conveyor means. By specifically sizing the perforations in the rotating seed removal tube in the roll box to pass the ginned seeds into the hollow center of the rotating tube and conveying these ginned seeds outside of the gin through the tube, thus continuously removing them from the center portion of the seed roll, a predominance of unginned cotton is maintained in the outer peripheral layer of the seed roll to engage the teeth of the saws at the ginning point and markedly increase the ginning capacity, for example up to about 50 percent increase in capacity. This both reduces the density of the seed roll and also reduces the amount of seed trying to get out of the roll box through the entrance region at the top of the zone between the ginning ribs and huller ribs where incoming unginned cotton is trying to enter, thus permitting the teeth of the cylinder saws to be loaded to full capacity.
Efforts have been made in the past to remove "trash or foreign matter" or "hulls or trash" from the roll box of saw type cotton gins of the earlier lower capacity types. Examples of this are found in the Raynor U.S. Pat. No. 2,743,484 providing a fixed perforated tube in the roll box having perforations sized to pass the "trash or foreign material" into the tube for suction withdrawal from the gin stand, or the Olmstead U.S. Pat. No. 26,516 where a driven rotating "cylindrical screen" in the roll box surrounds a revolving "spiral screen" sized to remove "hulls or trash" still attached to cotton in the roll box after passage through the hulling ribs. Jennings U.S. Pat. No. 3,135,021 shows a "rotary rib" type cotton gin wherein a fixed perforated tube is provided so that "dirt can readily get out of the seed roll" and thus produce a "higher grade" of ginned cotton. Also, the Cumpston U.S. Pat. No. 2,149,669 provides a perforated tube in the roll box which is supplied with hot air to assist in drying the cotton and "aid in turning the roll", and the Cotton U.S. Pat. No. 1,341,168 discloses, in a low capacity gin, a perforated fixed tube in the roll box and an inner driven conveyor screw for withdrawing "partially ginned cotton" which is then transferred into a "linter where it is stripped of every particle of merchantable lint". However, we are aware of no prior patents proposing the provision of a driven hollow perforated tube in the central region of the roll box of a saw type gin stand having perforations sized deliberately to pass the ginned cotton seed from the center region of the seed roll into the hollow center portion of the perforated tube where it is conveyed transversely out of the roll box and gin stand to a ginned seed collection facility to thus reduce the density of the seed roll and significantly reduce the quantity of ginned seed leaving the seed roll through the entrance to the roll box where it would continuously counter the introduction of new unginned cotton into the roll box, and by such an arrangement attain significant increases in ginning capacity such as we have realized.
An object of the present invention, therefore, is the provision of a novel saw type gin stand construction of the type having ginning ribs and hulling ribs coacting with a saw cylinder to gin cotton and defining a roll box overlying the zone between the ginning ribs and huller ribs, wherein a rotating perforated tube having openings sized to pass and withdraw ginned seeds from the seed roll is provided along with conveyor means for discharging the withdrawn ginned seeds transversely to a collection facility externally of the roll box, to significantly increase the ginning capacity of saw type gin.
Another object of the present invention is the provision of a novel saw type gin construction of the type described in the immediately preceding paragraph, wherein the perforated hollow tube in the roll box is continuously driven during operation of the gin in an appropriate direction and at an appropriate rate to assist in rotating the seed roll and increase the loading of lint onto the saw teeth to full capacity to optimize the ginning capacity of the gin stand.
Yet another object of the present invention is the provision of a novel arrangement of surface protrusions on the exterior surface of the perforated hollow tube in the roll box of a saw type gin stand as described in the immediately preceding paragraph, further enhancing the capacity increasing properties of the gin stand construction.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.